OATEY 72297 3" or 4" PVC General Purpose Pipe Fit Drain w/ 6" Cast NI Grate & Square Top

Both. The Oatey 72297 is a pipe fit drain, so the body accepts either 3 inch or 4 inch PVC pipe directly, no adapter or caulking. Pipe fit means the drain body slips over the pipe end rather than requiring a glued hub fitting, so you set your rough-in to whichever size the run already is.

It's a general purpose floor drain, not a shower pan drain. There is no clamping ring or membrane flange in the description, so it is not intended to clamp a shower liner. Use it where a floor drain pipes straight into a 3 inch or 4 inch PVC run, such as mechanical rooms, utility areas, and janitor spaces. For a tiled shower or a hot mop pan you want a dedicated shower drain with a membrane clamp.

A 6 inch cast nickel bronze grate on a square top. The cast metal grate is the part that takes traffic, which is why it is specified in cast NI rather than plastic, while the drain body itself is PVC.

No trap is included. The 72297 is the drain body and grate only; it fits onto the 3 inch or 4 inch PVC pipe you run to it, so the P-trap and the pipe to the branch line are separate items on your material list.

The assembly weighs 5.8 lb, nearly all of it in the 6 inch cast nickel bronze grate. That matters if you are ordering a quantity for a multi-unit job and figuring freight, and it tells you the grate is a real cast metal top rather than a light plated stamping.